This prospective randomized study analyzed 80 patients that underwent flexible bronchoscopy. Patients were randomly assigned to four groups of 20 patients each according to the anesthetic combination used: 200 mg topical lidocaine (LID group); 200 mg topical lidocaine and 2 mg/kg propofol (PPF group); 200 mg topical lidocaine and 20 mcg/kg alfentanil (ALF group); or 200 mg topical lidocaine and 0.05 mg/kg midazolam (MID group). Scores were assigned to patients according to the different variables observed during the endoscopic procedure; the lower the score, the lower the complication index.